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From: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
To: "Michael S . Tsirkin" <mst@redhat.com>,
	Igor Mammedov <imammedo@redhat.com>
Cc: Sia Jee Heng <jeeheng.sia@starfivetech.com>,
	Ani Sinha <anisinha@redhat.com>,
	qemu-devel@nongnu.org,
	Alistair Francis <alistair.francis@wdc.com>,
	Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
Subject: [PATCH v2] hw/acpi: correct field sequence in SPCR table
Date: Thu, 26 Mar 2026 15:48:35 +0100	[thread overview]
Message-ID: <20260326144835.67911-1-heinrich.schuchardt@canonical.com> (raw)

On LoongArch and RISC-V invalid SPCR tables are created:

Terrminal Type : 00
Language : 03

The correct values are:

Terrminal Type : 03
Language : 00

This is due to commit 7dd0b070fa09 ("hw/arm/virt-acpi-build.c: Migrate
SPCR creation to common location") that swapped the fields.

See the specification of the table in
https://learn.microsoft.com/en-us/windows-hardware/drivers/bringup/serial-port-console-redirection-table

This page shows version 1.10. But the sequence of the fields was not changed
since version 1.0.

Our LoongArch and ARM code uses version 1.07 of the specification.
Our RISC-V code uses version 1.10 of the specification.

Fixes: 7dd0b070fa09 ("hw/arm/virt-acpi-build.c: Migrate SPCR creation to common location")
Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
Origin: https://lore.kernel.org/qemu-devel/20260326121947.51200-1-heinrich.schuchardt@canonical.com/T/#u
Bug-Ubuntu: https://bugs.launchpad.net/ubuntu/+source/qemu/+bug/2146419
---
v2:
	Mention the different specification versions used by our code.
v1:
	https://lore.kernel.org/qemu-devel/20260326121947.51200-1-heinrich.schuchardt@canonical.com/T/#u
---
 hw/acpi/aml-build.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/hw/acpi/aml-build.c b/hw/acpi/aml-build.c
index 4b37405088..a999320e61 100644
--- a/hw/acpi/aml-build.c
+++ b/hw/acpi/aml-build.c
@@ -2115,10 +2115,10 @@ void build_spcr(GArray *table_data, BIOSLinker *linker,
     build_append_int_noprefix(table_data, f->stop_bits, 1);
     /* Flow Control */
     build_append_int_noprefix(table_data, f->flow_control, 1);
-    /* Language */
-    build_append_int_noprefix(table_data, f->language, 1);
     /* Terminal Type */
     build_append_int_noprefix(table_data, f->terminal_type, 1);
+    /* Language */
+    build_append_int_noprefix(table_data, f->language, 1);
     /* PCI Device ID  */
     build_append_int_noprefix(table_data, f->pci_device_id, 2);
     /* PCI Vendor ID */
-- 
2.53.0



                 reply	other threads:[~2026-03-26 14:49 UTC|newest]

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